| 摘要 |
PROBLEM TO BE SOLVED: To improve detection accuracy by suppressing erroneous detection in a device for detecting a disconnection abnormality of a multiplex communication system where communication is performed by a differential signal using a potential difference of two communication lines.SOLUTION: A disconnection detecting circuit 3 includes: a comparator 41 which outputs a high signal by an abnormality (disconnection) in the potential of CAN-H; a comparator 42 which outputs a high signal by an abnormality (disconnection) in the potential of CAN-L; a CAN receiver 15a which outputs a high signal in the recessive state of a bus 10; and AND circuits 43 and 44. In a dominant state that cannot occur during one-side disconnection, a low signal is output from the CAN receiver 15a, so that an output signal from the AND circuit 43, 44 to a microcomputer 17 becomes a low signal without fail. Namely, in the dominant state, disconnection is not determined in the microcomputer 17, thereby suppressing erroneous determination. |
